Various cardiac medical procedures are performed using transapical delivery of medical devices to the left or right ventricle. The ventricle is accessed directly through a passage formed through the myocardium near the apex of ventricle. Such medical procedures include valve replacement, such as aortic or mitral valve replacement, and valve repair, such as mitral valve repair. Conventional transapical delivery procedures typically are performed under general anesthesia, and include performing a small thoracotomy, spreading the ribs using a mechanical retractor, opening of the pericardial sac, suturing the hole made through the ventricle, and closing the thoracotomy.
U.S. Pat. No. 7,060,084 to Loshakove et al., which is incorporated herein by reference, describes a device for sealing a hole in a blood vessel, comprising a ring; a plurality of spikes extending from said ring towards a center of said ring, and to first direction along an axis of said ring, said spikes being adapted for engaging a blood vessel; and a plurality of tabs extending substantially radially from said ring. Rotating said tabs around said ring distorts said ring such that said spikes are rotated in a same direction as said tabs.
US Patent Application Publication 2005/0273129 to Michels et al., which is incorporated herein by reference, describes medical techniques for accessing an anatomical space of the body and particularly for penetrating the epicardium to access pericardial space and the epicardial surface of the heart in a minimally invasive manner employing suction. The distal end of a tubular access sleeve having a sleeve wall surrounding a sleeve access lumen and extending between a sleeve proximal end and a sleeve distal end having a plurality of suction ports arrayed around the sleeve access lumen distal end opening is applied against an outer tissue layer. Suction is applied through the plurality of suction ports to a plurality of portions of the outer tissue layer. A perforation instrument is introduced through the sleeve access lumen to perforate the outer tissue layer to form an access perforation into the anatomic space while the applied suction stabilizes the outer tissue layer, whereby further treatment drugs and devices can be introduced into the anatomic space.
PCT Publication WO 2008/044147 to Chatel, which is incorporated herein by reference, describes a device for the implantation of an apparatus on or in a mammalian internal organ, comprising: a tube for passing the apparatus through, one end of which is intended to be applied to a site chosen for the implantation of the apparatus, and the other end of which is intended to emerge outside the body of the mammal; fixing means suitable for fixing the device on the organ and for applying the end of the tube to the chosen site, said means being controlled from outside the body; and rigidifying means suitable for rigidifying the device, said means being controlled from outside the body, so as to fix the position of the tube relative to the fixing means and to the organ, once the device has been fixed on the organ and the end of the tube has been applied to the chosen site by the fixing means.
US Patent Application Publication 2007/0049952 to Weiss, which is incorporated herein by reference, describes a method and apparatus for repairing the heart's mitral valve by using anatomic restoration without the need to stop the heart, use a heart-lung machine or making incisions on the heart. The method involves inserting a leaflet clamp through the heart's papillary muscle from which the leaflet has been disconnected, clamping the leaflet's free end and then puncturing the leaflet. One end of a suture is then passed through the hollow portion of the clamp, while the other end of the suture is maintained external to the heart. The clamp is then removed and the suture's two ends are fastened together with a securement ring/locking cap assembly to the heart wall exterior, thereby reconnecting the leaflet to the corresponding papillary muscle. The introduction of the clamp, puncturing of the leaflet, passage of the suture therethrough and removal of the clamp can be conducted a plurality of times before each suture's two ends are fastened to the securement ring/locking cap assembly.
US Patent Application Publication 2008/0306333 to Chin, which is incorporated herein by reference, describes apparatus and method for performing surgical procedures within the mediastinum and within the pericardium include an endoscopic cannula having a transparent tip, and an endoscope for introduction into the mediastinum and optionally into the pericardium via a single subxiphoid incision. A cavity may be initially dilated for advancing the endoscopic cannula using a dilating tool that exerts a lateral-expansive force against surrounding tissue for evaluating the endoscopic cannula to be introduced into the mediastinum. Other surgical instruments are positioned through the endoscopic cannula to cut a flap of the pericardium as an opening through which other surgical apparatus may be introduced. The endoscopic cannula may be swept around selected regions of the heart through an aperture near the apex of the heart to facilitate placement of epicardial tacks about regions of the heart.
Semple T et al., in an article entitled, “Left Heart Catheterization by Direct Ventricular Puncture,” Brit. Heart J., 1968, 30, 402, which is incorporated herein by reference, describe a method of obtaining pressure gradient readings across the aortic and mitral valves by the use of a needle-type Teflon catheter introduced to the ventricle directly through the chest wall at the cardiac apex. After evaluating the method in dogs, the authors employed the method in a pilot study of 55 patients.
Medtronic, Inc. manufactures the Octopus® family of tissue stabilizers, which are reusable tissue stabilizers with collapsible suction pods that enable insertion into and removal from the thoracic cavity through a port, thus eliminating the need for an incision for insertion of the stabilizer.
The following publications, all of which are incorporated herein by reference, may be of interest:
U.S. Pat. No. 4,723,940 to Wiegerinck
U.S. Pat. No. 5,685,856 to Lehrer
U.S. Pat. No. 5,865,809 to Moenning et al.
U.S. Pat. No. 6,080,175 to Hogendijk
U.S. Pat. No. 6,338,710 to Takahashi et al.
U.S. Pat. No. 6,786,898 to Guenst
U.S. Pat. No. 7,146,225 to Guenst et al.
U.S. Pat. No. 7,189,201 to Borst et al.
U.S. Pat. No. 7,338,441 to Houser et al.
U.S. Pat. No. 7,534,260 to Lattouf
US Patent Application Publication 2004/0138522 to Haarstad et al.
US Patent Application Publication 2006/0241544 to Haverich
US Patent Application Publication 2006/0247672 to Vidlund et al.
US Patent Application Publication 2009/0082620 to Haarstad et al.
Shape memory alloys are a group of materials that, after being deformed, return to a predetermined shape when heated. This memory effect is caused by a temperature-dependent crystal structure. One-way shape memory alloys remember a single shape, to which they return upon being heated. Two-way shape memory alloys remember two different shapes, the first at a relatively low temperature, and the second at a higher temperature.
The following references, all of which are incorporated herein by reference, may be of interest:
Featherstone et al., “Improving the speed of shape memory alloy actuators by faster electrical heating,” In Proceedings of the Ninth International Symposium on Experimental Robotics, Paper ID 128 (2004)
Roubí{hacek over (c)}ek et al., “Thermodynamics of shape-memory alloys under electric current,” Zeitschrift für Angewandte Mathematik and Physik (ZAMP) (June 2009)